オウギガニ

During low tide on the 20th August 1967, two berried pilumnid crabs, Pilumnopeus indicus (de Man) and Heteropilumnus ciliatus (Stimpson) of the family Xanthidae were taken at the rocky shore of Tsuyazaki, Fukuoka Prefecture. The first zoeae of both species were hatched next day, but the subsequent stages could not be obtained. In P. indicus all zoeae were dead the day after tomorrow, whereas in H. ciliatus they lived for six days. The characters of the first zoeae are as follows. 1) Pilumnopeus indicus (de Man). The cephalothorax (0.5 mm long) has only the dorsal spine (0.2 mm long) which is considerably shorter than the antennae (Fig. 1). The abdomen is composed of five segments and the telson, its total length being 0.7 mm. The lateral surfaces of the second abdominal segment are furnished with a lateral knob on both sides, which is not acute and slightly curves anteriorly at its tip. The posterolateral margins of the third to fifth abdominal segments terminate as small spines which overlap the next segment. The telson (Fig. 2k) has a lateral spine on each prong and three pairs of hairy spines on its inner surface. The antennule (Fig. 2c) has two terminal aesthetes and one smaller seta. The protopod of the antenna (Fig. 2d-e) forms a tapering process which bears some short spines on the distal